2579 replies to this topic

[Bob Perry]

Gate:
I think the answer to that question is pretty much the same for all good boats, beam reacing in 18 knots TWS.
When I look at VPP's I look for best VMG to weather, best VMG downwind and the top boat speed for any wind speed.
The VPP's shw the boat to be very close winded but I am a bit dubious of the figures so I have to be a cautious in evaualing upwind VMG for a boat like this. I'm not usre the boat will delver what ther VPP program says it will.
Somehow I can't see a ketc like this pointing with an AWA of 28 degrees. It would be nice though. I'd be very happy with AWA of 30 degrees.

Sons:
Nice pics of KIALOA. The point I was makoijg in the GOB article on rigs was that thr yawl rig was the favorite rig under the CCA. But ketches hade the same advantage. I think putting more area into the main and fore triangle while carrying a smaller mizzen was the best combo for speed under that rule.

[Tanton Y_M]

I can hear Bob..."You big dummy!"

Good job, both of you.
I have always liked a pilothouse treatment such a shown on the rendering
This photo does not show it well but the raised roof aft, even in small way gives a 360 deg. vision.  851pic1.jpg   52.97K   151 downloads  851pic1.jpg   52.97K   151 downloads Without having to go on deck

[Bob Perry]

Thanks Yves-Marie. It's alwys nice to get one of your old boss's approval.

[Soñadora]

Sons:

See the winch pod? The bulge? We have a slight problem there as the rolled of house top does not continue in the area of the bulge. The way you have it now the eyebrow trim piece is standing proud of the house top surface at the bulge. That does not look right to my eye. Could you look at this and see if there is a graceful way to resolve that transition. We may need to continue the radius all around the bulge. Thanks.

Will do Bob. Working on that eyebrow. I think you'll like the results.

[The Advocate]

Kudos to Mr and Mrs Lucky Owner for developing such a highly personalised interior plan, that meets their needs without regards to resale or anything else.

Not what I would have, but that is the point. I'll just print it out and find my red pencil, sit down with a tall glass of Milo, some Vegimite on toast and have have a perfectly enjoyable Sunday morning.

Still a gorgeous boat Bob.

[Paps]

some pics of Kialoa

Very cool Sons.

Back in the 70's Kialoa and Windward Passage were doing the Hobart race. They were off the NSW coast flying everything they could find with Kialoa about a mile ahead. Without any warning at all the wind shifted almost 180 and everything on K was inside out! The had to turn around to get everything filled again so they could start getting it down. For a few crazy minutes the two boats were sailing directly at each other under full sail!!!!

An ABC chopper got the whole scene on film it was incredible.

[Soñadora]

Paps

cool info. There's no denying the awe at seeing a boat like that with every sail up. Definitely enough there to keep a large crew busy.


An unrendered view of the transom showing the baby stays for the aft stay.

This boat is taxing my computer. I'm unable to use the high end illumination settings as it completely obliterates my 4GB of RAM.

Time for an upgrade!

Attached Files

•  transom.JPG   346.35K   120 downloads

[Great Red Shark]

Ad:
No. I won't publish the specs. Too much work too much information to just give those away.
I'll post a drawing of the interior tomorrow.
If by "specs" you mean primary dimensions try these:
LOA 57.18'
DWL 47.93'
Beam 15.00'
Draft 7.00'
Displ 45,000 lbs half load

Ha HA ! ( Snidley Whiplash voice)

Now I shall simply build my own, for pennies...you fool !



Seriously though guys, nice work - looks very balanced for such a big boat, I like how the PH works with the traditional design, and the light color is better in warm temps to keep it cool - looking at the details like the hatch hinges I get a feeling for the level of resolution you are working at, but my inner deck-ape just obsesses about the sheets, travelers, leads,etc. so when I see the booms floating in space devoid of controls I just get fidgety.

Thank you for the glimpse on the project, I hope it goes forward to everyone's satisfaction.

[Soñadora]

Those booms are a work in progress. Running rigging is typically the biggest challenge for the exterior, so I save that for last.

In the meantime, here's a movie you can watch:

http://sail2live.com.../Movie_0001.wmv

[Great Red Shark]

Sure, I can see that - versus the other end of the race-boat design loop, -- where you know how you want it to work and then design the deck to fit THAT - thinking of stuff like those odd 'trimmer's trenches' on the Elliot 'Peacemaker' and all manner of race-optimization ( German mainsheets, multiple daggerboards, etc) -- has got to far more nuanced. I look forward to seeing how you make it work and not look like an either a Wally or and erector set.

Thanks again, the 'movie' is cool, and gives a different impression with it's dynamic perspective. Like many real cruisers, the cockpit is surprisingly 'snug'. Not so sure about those PH-top winches, either - more like a powered winch at the house level, inside the PH - would be my first thought.

[Cruisin Loser]

This boat is taxing my computer. I'm unable to use the high end illumination settings as it completely obliterates my 4GB of RAM.

Time for an upgrade!

Memory is cheap, especially compared to maintaining brightwork.

Do we need to pitch in to buy more RAM? These renderings are well worth it to some of us. Give me a paypal # and I'll pitch in. It's like internet porn, only the wife approves.

[Cruisin Loser]

OK, I watched the movie, mine will lose the hull ports, have SS rails over the dorades, and have a molded (instead of bright) seahood over the CC companionway. I'll drop the varnished cabin trunk and have bright handrails instead. In nice weather I'll be steering from the CC with the autopilot remote in my pocket, popping down to the galley from time to time to see how the bride is coming along with the warm crab quesadillas and honeydew melon with fresh lime, iced tea with bruised mint leaves. Shit, nice work Sons, really nice work. That's cool as hell.

[Jose Carumba]

Maybe down the road a render farm is in order if SW can do distributed fendering. It really speeds up the process. You can build one from inexpensive dual or quad core boxes, since in rendering it's the CPU that does all the work. Now that there are some good GPU rendering engines coming out, that may change.

[Craig Smith]

I wanted no bowsprit. Lost that one too. But I do see it's advantages.
...
So we began with a shape that had some overhangs and that's how the general look came about.

I was going to mention this above too but thought it must have been your own intent.

Why the enclosed bowsprit for the anchor(s)? (Neither Rick's renders nor your drawing shows any stay attachments so I'm assuming it's just for the anchors). You have an enclosed quasi-platform which is a real PITA in general, can't remove the anchor without dropping it out - real nuisance stowing the anchor for a passage when you're not at a dock. Then you won't easily fit any modern efficient anchor, will have problems either with the roll-bar striking on the bars or there's not enough room for an adequately sized anchor to sort itself out if it comes up upside-down etc. Lastly the support bar in the place of the bob-stay will foul the chain when deployed as the boat veers. Retrieval will be horrible. We really hate this type of set-up.

[The Advocate]

So now it is read the book, seen the movie, sail the dream?

I wonder if I am actually seeing some differences in Sons renderings to the plans???

[savoir]

The position of the anchor is different - maybe 1ft further forward on the plan.

[Soñadora]

lucky you. Me and Jack had a discussion.

RAM isn't the problem. I need to switch to a 64bit system. It's in the works...

Render Farm.... Check this puppy out:

24-core render farm made from IKEA furniture

For animations, a render farm is the only way to go. For stills, the desktop box has to have some major balls.

now, to answer the 'differences in plans vs. the rendering'

I was whining about that earlier. I grew up drawing 3-view mechanical stuff on a board with a pencil. Well, I haven't grown up yet, but that's besides the point. Projecting a 2D drawing into a 3D model often gives some unexpected results. BUT. That's to be expected. Talk about your oxymorons! I use the plans EXPLICITLY to project into 3D. Literally...I take the profile and plan views and using some really cool commands, intersect those two in 3D space. I'm projecting what is drawn into that space. I do not alter anything from the plans.

BUT

With that said, the 2D plans do not show everything. For example, it's difficult to show what the actual draft (cabin slope) will look like in 2D. It's difficult to show projected portlites in 2D. And on and on. So I work with the designer when there's discrepencies to figure out what we really are looking for. That may result in the 3D model not looking exactly like the 2D model. Adjustments have to be made. But that's the advantage of working in 3D. You encounter a lot of 'A HA!' moments when you realize something drawn in 2D will look a particular way in 3D.

These models are meant to give a very, very close representation of what the finished product will be like. It's a much more faithful approach than 2D drawings. However, it's not the last word. When the boat is built, mockups are made and the whole design is worked out in REAL 3D. It would be great if the 3D model would be the last word, but the truth is that even 3D computer models miss some things.

I do believe that will change. For some boats, it already has. Highly accurate models start life as 3D (not 2D) and go directly to a mill where a plug is turned out in a matter of hours. I will admit to not being as savvy or having the kinds of tools (Catia, Maxsurf, etc) that could take it to that level, but my models give the client a very good sense of what the boat will be like when it's done.

It's an iterative process. While this particular model looks terrific (IMNSHO), it's not complete. Please keep that in mind. When it is complete, you'll see it here

[savoir]

The timber bits are incredibly realistic. It's like the breakthrough when cartoon animators figured out how to put hair on animals. That overhead angle of the aft cockpit is a beauty.

[The Advocate]

lucky you. Me and Jack had a discussion.

RAM isn't the problem. I need to switch to a 64bit system. It's in the works...

Render Farm.... Check this puppy out:

24-core render farm made from IKEA furniture

For animations, a render farm is the only way to go. For stills, the desktop box has to have some major balls.

now, to answer the 'differences in plans vs. the rendering'

I was whining about that earlier. I grew up drawing 3-view mechanical stuff on a board with a pencil. Well, I haven't grown up yet, but that's besides the point. Projecting a 2D drawing into a 3D model often gives some unexpected results. BUT. That's to be expected. Talk about your oxymorons! I use the plans EXPLICITLY to project into 3D. Literally...I take the profile and plan views and using some really cool commands, intersect those two in 3D space. I'm projecting what is drawn into that space. I do not alter anything from the plans.

BUT

With that said, the 2D plans do not show everything. For example, it's difficult to show what the actual draft (cabin slope) will look like in 2D. It's difficult to show projected portlites in 2D. And on and on. So I work with the designer when there's discrepencies to figure out what we really are looking for. That may result in the 3D model not looking exactly like the 2D model. Adjustments have to be made. But that's the advantage of working in 3D. You encounter a lot of 'A HA!' moments when you realize something drawn in 2D will look a particular way in 3D.

These models are meant to give a very, very close representation of what the finished product will be like. It's a much more faithful approach than 2D drawings. However, it's not the last word. When the boat is built, mockups are made and the whole design is worked out in REAL 3D. It would be great if the 3D model would be the last word, but the truth is that even 3D computer models miss some things.

I do believe that will change. For some boats, it already has. Highly accurate models start life as 3D (not 2D) and go directly to a mill where a plug is turned out in a matter of hours. I will admit to not being as savvy or having the kinds of tools (Catia, Maxsurf, etc) that could take it to that level, but my models give the client a very good sense of what the boat will be like when it's done.

It's an iterative process. While this particular model looks terrific (IMNSHO), it's not complete. Please keep that in mind. When it is complete, you'll see it here

Sons, don't sweat it, I was just trying to get a spot the difference competition going!

Renderings are sweet mate.

[Paps]

I used to love those in the PIX/POST, always figured them out too!!!!

[Tom Ray]

An unrendered view of the transom showing the baby stays for the aft stay.

Has it been decided what is going to hang there?

Looks like any dinghy cranked all the way up will hit those baby stays. Or are the davits long enough to keep the dinghy outside them?

[CharlieCobra]

Nice work guys. Good looking boat. You can tell I've been out of the WLYDO for a while.

[Jose Carumba]

RAM isn't the problem. I need to switch to a 64bit system. It's in the works...

Render Farm.... Check this puppy out:

24-core render farm made from IKEA furniture

For animations, a render farm is the only way to go. For stills, the desktop box has to have some major balls.

64 bit will definitely help. Yeah I saw that render farm before. It's pretty cool and not hard to do. While render farms are widespread in the film CG industry they definitely do help for stills if you are using rendering software which supports distributed rendering. The software we use (Maxwell) does it, and using 2 machines on our network we can cut the rendering time down considerably.

When the boat is built, mockups are made and the whole design is worked out in REAL 3D. It would be great if the 3D model would be the last word, but the truth is that even 3D computer models miss some things.

Yes, this is so true. Sometimes there's nothing like the ol' Mk 1 Mod 0 eyeball on a mockup to help sort things out. Customers don't always ahve the ability to decipher 2D drawings or even 3D renderings. Sometimes they need to walk through a mockup to truly "see" what the design is like.

Highly accurate models start life as 3D (not 2D) and go directly to a mill where a plug is turned out in a matter of hours. I will admit to not being as savvy or having the kinds of tools (Catia, Maxsurf, etc) that could take it to that level, but my models give the client a very good sense of what the boat will be like when it's done.

Actually Sons, you do have those tools. You can export IGES or STEP files from SW or Rhino and send them to a 3D tooling firm and have them cut. We do this all the time with very complicated parts using only Rhino.

And yes the model looks terrific. Keep it up.

[c-hag]

omg----as much as i love my old garden--yeah-i have one--LOL-- i like perry designs, also--my 2 favorite designers---i thought this was a sweet boat--i was dead wrong---
it is f*****g sweet. another notch for perry's belt.

[Bob Perry]

Hag:
I don't see you here often. Thanks for the kind words.
I'd like to know who the other designer is.

OK, I get it. It's Bill Garden. I am humbled by the company. I'm no Bill Garden. My boats sail better. (cheap ass swipe).

[Gatekeeper]

OK, I get it. It's Bill Garden. I am humbled by the company. I'm no Bill Garden. My boats sail better. (cheap ass swipe).

And for the whole story you'll have to buy Bob's book...

[Hike, Bitches!]

Go the Kialoa!

[Soñadora]

RAM isn't the problem. I need to switch to a 64bit system. It's in the works...

Render Farm.... Check this puppy out:

24-core render farm made from IKEA furniture

For animations, a render farm is the only way to go. For stills, the desktop box has to have some major balls.

64 bit will definitely help. Yeah I saw that render farm before. It's pretty cool and not hard to do. While render farms are widespread in the film CG industry they definitely do help for stills if you are using rendering software which supports distributed rendering. The software we use (Maxwell) does it, and using 2 machines on our network we can cut the rendering time down considerably.

When the boat is built, mockups are made and the whole design is worked out in REAL 3D. It would be great if the 3D model would be the last word, but the truth is that even 3D computer models miss some things.

Yes, this is so true. Sometimes there's nothing like the ol' Mk 1 Mod 0 eyeball on a mockup to help sort things out. Customers don't always ahve the ability to decipher 2D drawings or even 3D renderings. Sometimes they need to walk through a mockup to truly "see" what the design is like.

Highly accurate models start life as 3D (not 2D) and go directly to a mill where a plug is turned out in a matter of hours. I will admit to not being as savvy or having the kinds of tools (Catia, Maxsurf, etc) that could take it to that level, but my models give the client a very good sense of what the boat will be like when it's done.

Actually Sons, you do have those tools. You can export IGES or STEP files from SW or Rhino and send them to a 3D tooling firm and have them cut. We do this all the time with very complicated parts using only Rhino.

And yes the model looks terrific. Keep it up.

I guess what I was thinking is that I don't have the tools to do it right. After many, many, many tries, I do not have confidence with SolidWorks's ability to build a fair hull from scratch. Yes, I could do it in Rhino, but in that case I don't have confidence in MY ability yet (guys like you and Bob are a big help ).

Glad you like the model. I was a bit pasted back there with my rant.

[PNW Matt B]

What's the limitation on 64-bit? I'd be shocked if your modeling software doesn't support it.

A render farm is not complicated to build, but it's a bit of a bitch to maintain and keep in top condition. It might be easier and cheaper to lease time on an existing farm, but that requires some management skill. I don't have the skills to do more than admire Bob's designs or Sons' models, but a server farm and its management is something I can do in my sleep.

[floating dutchman]

One thing I'm not sure about the rig, Is it a Ketch, a Cutter-Ketch or a Cutter-ketch that will be sailed as a Ketch?(choice of headsails)

I'm still not sold on that centre cotpit, I can't visualise what happens with the space below, Is the cabin top a false one?

Dam fine looking yacht, I can see the hours gone in getting it right! That aft cotpit is pure genius

[The Advocate]

I think I would describe it as a cutter rigged ketch.

[Paps]

Bob, you are the Bill Garden (equivalent) of our generation, and I mean that in a nice way, holding aloft the required teaspoon. Take a (small) bow my friend, you have influenced yacht design in our era more than most, and in the cruising category, stand above the rest.

Not only that but you have, via forums interacted with the collective "us" on many levels. Speaking personally it has been a pleasure and an experience. Wassail.

[The Advocate]

OK, I've been quite on this particular subject since Bob and Sons dropped this beauty on the desk, but quiet I can be no longer.

I must say at this junction, that I am most disappointed with some of the regulars here. Such a critical and palpable detail has been missed and not commented on, and I find that unpardonable, given the respect I have for the assembled on these pages.

Shame, shame, shame.

Well done Bob on slipping this little nugget through to the keeper.

[olaf hart]

I don't know what you are on about, all the hatches are on the centerline.

[The Advocate]

I did notice that, but that is not it.

[Gatekeeper]

As drawn...the backstay configuration for the mizzen mast interfers with the davits??

[savoir]

OK, I've been quite on this particular subject since Bob and Sons dropped this beauty on the desk, but quiet I can be no longer.

I must say at this junction, that I am most disappointed with some of the regulars here. Such a critical and palpable detail has been missed and not commented on, and I find that unpardonable, given the respect I have for the assembled on these pages.

Shame, shame, shame.

Well done Bob on slipping this little nugget through to the keeper.

What ? Did Bob forget the drinks locker ?

[The Advocate]

As drawn...the backstay configuration for the mizzen mast interfers with the davits??

If you are referring to the davit bob stays interfering with the dinghy, has already been mentioned.

[The Advocate]

OK, I've been quite on this particular subject since Bob and Sons dropped this beauty on the desk, but quiet I can be no longer.

I must say at this junction, that I am most disappointed with some of the regulars here. Such a critical and palpable detail has been missed and not commented on, and I find that unpardonable, given the respect I have for the assembled on these pages.

Shame, shame, shame.

Well done Bob on slipping this little nugget through to the keeper.

What ? Did Bob forget the drinks locker ?

Go wash you mouth out.

As if Maestro would forget that. Chances are that was the first thing on the page, then the other necessary details used to keep it afloat were drawn around it.

[Soñadora]

What's the limitation on 64-bit? I'd be shocked if your modeling software doesn't support it.

A render farm is not complicated to build, but it's a bit of a bitch to maintain and keep in top condition. It might be easier and cheaper to lease time on an existing farm, but that requires some management skill. I don't have the skills to do more than admire Bob's designs or Sons' models, but a server farm and its management is something I can do in my sleep.

the limitation is that I'm not currently running a 64 bit OS . That will change this week.

[Soñadora]

Ad

  my close proximity to this project does not permit me to participate

[Bob Perry]

It is my hope that the shape of the dinghy ( I don't know what dinghy it is yet so I have been using the custom dink I did for JAKATAN on the drawings) will snug up under the davits and just miss hitting the mizzen "bobstays?" we need anorher word for these wires. The actual chainplate location is flexible and we can verify this with either 3D modelling (think Sons) or an actual mockup. Davit length may needto be adjusted but in the end I will make it work.

Ad:
You have me puzzled.

Paps:
Thanks. I live in a fairly remote area. I spend each day with the dog and the cat and seldom have vistors. CA has become my social life. I've made some good friends here. It's a bit odd but it works for me.

[Gatekeeper]

It is my hope that the shape of the dinghy ( I don't know what dinghy it is yet so I have been using the custom dink I did for JAKATAN on the drawings) will snug up under the davits and just miss hitting the mizzen "bobstays?" we need anorher word for these wires. The actual chainplate location is flexible and we can verify this with either 3D modelling (think Sons) or an actual mockup. Davit length may needto be adjusted but in the end I will make it work.

Bob

I've been intrigued by the dinghy issue...if the two "bob stays" where properly padded could the dinghy be drawn up with and against them. It would probably rest on about a 35-45 degree angle...securing the motor might take some thought, but I'm sure it's doable.

The dinghy would be better secured and the modifications less involved.

Just my 2 cents.

[Bob Perry]

Gate:
I've been thinking the same thing. Could work out fine. The bow end is no problem as the ataper of the hull shape should provide the clearance. In the stern end it will be a matter of fractions of an inch.

Note that if you look closely at the renderings and drawings the dink will also stow on the forward cabin trunk. I belive Sons has drawn the chocks in. The dink will sit over the butterfly hatch.

[Gatekeeper]

Gate:
I've been thinking the same thing. Could work out fine. The bow end is no problem as the ataper of the hull shape should provide the clearance. In the stern end it will be a matter of fractions of an inch.

Bob

Andrew always brings me his old British yacht mags, and they show a owner built system of lifting and securing a dinghy our size (WB 8) crossways on the transom...after considering the boat in question here, I may consider reconfiguring my (crappy) davits for this task.

I hate threads like this...I get great ideas, which result in more work, and more $$

Damn you Sons!!

[Tom Ray]

OK, I've been quite on this particular subject since Bob and Sons dropped this beauty on the desk, but quiet I can be no longer.

I must say at this junction, that I am most disappointed with some of the regulars here. Such a critical and palpable detail has been missed and not commented on, and I find that unpardonable, given the respect I have for the assembled on these pages.

Shame, shame, shame.

Well done Bob on slipping this little nugget through to the keeper.

Did we forget to ask what it rates or something?

[Jose Carumba]

OK, I've been quite on this particular subject since Bob and Sons dropped this beauty on the desk, but quiet I can be no longer.

I must say at this junction, that I am most disappointed with some of the regulars here. Such a critical and palpable detail has been missed and not commented on, and I find that unpardonable, given the respect I have for the assembled on these pages.

Shame, shame, shame.

Well done Bob on slipping this little nugget through to the keeper.

Hah! No stripper pole!

[Soñadora]

I'm gonna say that a dinghy snugged up and angled to match the stays would be too much 'C-O-D-B'-ish (crap-on-de-back). The W/L of the dink needs to be dead on parallel with the W/L of the mother ship. I'm going to go out on a limb and what I know about this client in the short period that I've worked with him, I'm pretty sure he'd agree with that.<br /><br />
We'll figure out a way to make it work. It might involve creating a really shiny polished custom fitting attached to the davit. We want as much vertical force as we can get on those ass-baby stays so my preference would be to keep them as close to the W/L as possible.

[Bob Perry]

http://web.me.com/to...10/Welcome.html

If you want to see what goes on at the Perry Rendezvous check this link out.
The pics are by my pal TomL who posts here obnce and a while.

[Hike, Bitches!]

Gate:
I've been thinking the same thing. Could work out fine. The bow end is no problem as the ataper of the hull shape should provide the clearance. In the stern end it will be a matter of fractions of an inch.

Note that if you look closely at the renderings and drawings the dink will also stow on the forward cabin trunk. I belive Sons has drawn the chocks in. The dink will sit over the butterfly hatch.

Bob...make the dinghy a double-ender...problem solved.

[sailman]

http://web.me.com/to...10/Welcome.html

If you want to see what goes on at the Perry Rendezvous check this link out.
The pics are by my pal TomL who posts here obnce and a while.

Great shots! The one of the two kids on the bow reminded me of summertime cruising as a youngster.

[Jose Carumba]

Bob,

How about moving the davit crossbar a little further fwd, creating a backstay bridle which attaches to the davit arms in way of the crossbar and running some short stays from each arm to the transom. Also bury the davit arms deeply and buld them out of carbon. The short stays will have a better angle, the crossbar will take up the compression load and access to the dinghy through the stern gate is improved. can you do this and not impact the mizzen boom?

 transom-2.JPG   119.76K   86 downloads

[sailman]

Bob,

How about moving the davit crossbar a little further fwd, creating a backstay bridle which attaches to the davit arms in way of the crossbar and running some short stays from each arm to the transom. Also bury the davit arms deeply and buld them out of carbon. The short stays will have a better angle, the crossbar will take up the compression load and access to the dinghy through the stern gate is improved. can you do this and not impact the mizzen boom?

 transom-2.JPG   119.76K   86 downloads

Jose,

I don't see why you would have the stays go through the davit arms, they should have room to just go straight to the transom. Splitting it is a great idea to open up the stern for boarding or swim ladder access.

[Jose Carumba]

Bob,

How about moving the davit crossbar a little further fwd, creating a backstay bridle which attaches to the davit arms in way of the crossbar and running some short stays from each arm to the transom. Also bury the davit arms deeply and buld them out of carbon. The short stays will have a better angle, the crossbar will take up the compression load and access to the dinghy through the stern gate is improved. can you do this and not impact the mizzen boom?

 transom-2.JPG   119.76K   86 downloads

Jose,

I don't see why you would have the stays go through the davit arms, they should have room to just go straight to the transom. Splitting it is a great idea to open up the stern for boarding or swim ladder access.

I think the backstay needs to be aft in order to not interfere with the mizzen which is why it was positioned that way to begin with.

[sailman]

Bob,

How about moving the davit crossbar a little further fwd, creating a backstay bridle which attaches to the davit arms in way of the crossbar and running some short stays from each arm to the transom. Also bury the davit arms deeply and buld them out of carbon. The short stays will have a better angle, the crossbar will take up the compression load and access to the dinghy through the stern gate is improved. can you do this and not impact the mizzen boom?

 transom-2.JPG   119.76K   86 downloads

Jose,

I don't see why you would have the stays go through the davit arms, they should have room to just go straight to the transom. Splitting it is a great idea to open up the stern for boarding or swim ladder access.

I think the backstay needs to be aft in order to not interfere with the mizzen which is why it was positioned that way to begin with.

In that case, run the backstay to just behind the mizzen mast. It might limit roach on the main but if you've got a mizzen I don't think you're too concerned about getting that last 2% out of the main.

[Soñadora]

There's a drop-down transom on this baby.

[Jose Carumba]

There's a drop-down transom on this baby.

Yes but If you can move the 2 stays under the davit crossarm to the side you improve access and provide a better attachment for the backstay (Edit: and provide a little more room for the dinghy)., IMO..

[Bob Perry]

Jose:
OK, I see your sketch now. I can see that working with a spilit mizzen backstay. It's worth considering. Thanks.
Looking at Rick's rendering I think those chainplates need to go lower on the transom.
We'l;l fix that later.

[Soñadora]

Bob,

How about moving the davit crossbar a little further fwd, creating a backstay bridle which attaches to the davit arms in way of the crossbar and running some short stays from each arm to the transom.  Also bury the davit arms deeply and buld them out of carbon.  The short stays will have a better angle, the crossbar will take up the compression load and access to the dinghy through the stern gate is improved.  can you do this and not impact the mizzen boom?

 transom-2.JPG   119.76K   86 downloads

that's a great idea Jose. I asked about that early on and the decision was to use a single stay.

[Bob Perry]

Rick:
Just leave it as is for now but we may come back to this later. I'm not convinced I have a problem yet.
We can't move the cross beam forward much as it will impede the use of the flop down steps. But I don't think Jose's rig depend upon that anyway.

[palindrome]

Bob, just a thought, if the Davits are hard mounted why the need for a crossbeam in the first place?

Pal

[Gatekeeper]

Bob, just a thought, if the Davits are hard mounted why the need for a crossbeam in the first place?

Pal

Pal

I think the compression load would be more than we would want to trust to the davits without a crossbar....peace of mind if nothing else.

[The Advocate]

It is my hope that the shape of the dinghy ( I don't know what dinghy it is yet so I have been using the custom dink I did for JAKATAN on the drawings) will snug up under the davits and just miss hitting the mizzen "bobstays?" we need anorher word for these wires. The actual chainplate location is flexible and we can verify this with either 3D modelling (think Sons) or an actual mockup. Davit length may needto be adjusted but in the end I will make it work.

Ad:
You have me puzzled.

Paps:
Thanks. I live in a fairly remote area. I spend each day with the dog and the cat and seldom have vistors. CA has become my social life. I've made some good friends here. It's a bit odd but it works for me.

No, not the dinghy shape. Am sure that will change as the project progresses anyway.

[The Advocate]

OK, I've been quite on this particular subject since Bob and Sons dropped this beauty on the desk, but quiet I can be no longer.

I must say at this junction, that I am most disappointed with some of the regulars here. Such a critical and palpable detail has been missed and not commented on, and I find that unpardonable, given the respect I have for the assembled on these pages.

Shame, shame, shame.

Well done Bob on slipping this little nugget through to the keeper.

Hah! No stripper pole!

Good (very funny) point, but no. Perhaps the mizzen compression post could be moved a little.

[The Advocate]

There's a drop-down transom on this baby.

Ladies and Gentleman, we have a winner.

Unfortunately this breaches the terms and conditions laid out in a separate document which I forgot to post, and thus voids the prize of something from my desk.

Bob, I hope it is hydraulically operated!

For what it is worth, I would like to see it go closer to the water.

[Bob Perry]

I like the crossbar on the davits. It's a good place for the stern light.

Ad:
It's not that simple. It's a complex geometry problem and it has to work in the space available. It will essentially be the same arrangement that I out on JAKATAN. That works well. If I had started with the stern door in place I would have had some options but this feature was added when the design was well along.

[SemiSalt]

I think the compression load would be more than we would want to trust to the davits without a crossbar....peace of mind if nothing else.

I've been wondering about the compression on the curved arms of the davits. Also the bending moments on the crossbar. Is this a case of "carbon cures all"?

[Bob Perry]

Semi:
With carbon it is easy to overbuild and the davits will be plenty strong. The mizzen may in fact not even need that backstay so the load won't be great. But we'll design the davits plenty strong and carbon is perfect for the job.
JAKATAN's davits weighed 7 lbs each.

[The Advocate]

The dinghy issue.

Couldn't you rotate it 90 degrees so that it was fore and aft with a portion of it on the aft deck?

[Bob Perry]

Ad:
Have you looked at the deck plan?. It is under the sail plan I posted.
How would you access the transom door if the dinghy were resting on the deck? Ok, assume the dinghy will always be deployed when the transom door is used. That's reasonable but my way you can acces the door with the dinghy in the davits. I think aethetically the boat will look better with the dinghy in davits in the traditional manner. If you take the time to look at the deck layout aft you will see it is very "tight". The area is pretty mnuch driven buy the transom door. Outbaord of the transom door there is very little room. I do not have area to play with and devote to dinghy stowage on deck. I already have optional dinghy stowage on the cabin trunk and I think that is more than enough.

When you offer suggestions please keep in mind the domino effect of the change you are proposing. "If I change this I'll have to change that and if I change that I'll have to changes those things and on and on". As you wind your way down the design spiral and prioritize features towards a final design you will inevitably find your options are reduced.

[The Advocate]

Bob,

I have read the domino theory as prescribed and always try to keep that in mind.

As you suggest, the times the door is down, the dinghy will probably be down anyway.

I understand that the lucky owner has had a fair bit of input and is no doubt happy with the beauty you have penned on his behalf.

Please take my comments to be "If it were mine I'd...."

My partner is disabled on one side, and when I get around to having a boat like this, I must keep in mind her needs first and foremost. Hence the need for the steps to be closer to the water, and here is the domino, this means that there would not be enough space to open them with the dinghy there, so it would have to be down when we use the steps.

For us.

Hence the domino was considered.

Our issues are why I love your boats and interiors.

[The Advocate]

P.S;

I just blew up the plans and had a play.

You are correct, it is not feasible.

I should have known better, consider me self chastised.

Now if it were my boat, I might consider extending the aft section a little....

[Bob Perry]

Ad:
Ok, now go to your room.

In fact, my own rule for steps off a transom is that they should go down two step levels BELOW the dwl. This way you can climb the steps without any acrobatic ( and at my age impossible) contortions.
In the case of this design that will have to mean a removable ladder of some type. But my rule of thumb for a swim platform (and this is kind of a mini-swim step)is 18" to 20" above the DWL. I find this dimensions puts the steps at the height of the avareage dock. so that you can board the boat from the stern easily. The design here has the lower step at 18" above the DWL.

As for extending the "aft section a little bit" we have already pushed LOA from the original 50' to 57' and that's where I drew the line. We do have a budget and you can't expect to make the boat longer and longer wirthout stressing the budget. It's my job to keep the clent informed of cost adding changes. The funny thing is, that if you add 24" to LOA in oder to help with the swim platform, most clients would say "Hey, now I have another 24" can I have built in benson rack and a finigan table with those little poncy chairs?" It just never stops.

Let's say I was designing this boat for you and your partner. I would START the design wih the stern boarding arrangement. It would be a priority. When that feature was defined and refined I would move on to see what could be done with the adjacent features.

[The Advocate]

If I am going to my room, which of your books should I read first?

[Jose Carumba]

I've always wanted a place to store my bensons.

[palindrome]

Bob, maybe you have already considered this but to add clearance for the transom door, would it be possible to have the transom door itself hinge twice. Once at the normal attachment point and once athwartship so that the stair folds / cantilevers, back on itself to reduce clearance required to raise and lower it and then extends again to close . It would also give an option of changing pitch of the last section so it is either deeper in the water or just to the water as required for swimming or diving.

If my explanation makes any sense at all.

Pal

[Bob Perry]

Pal:
I think I'd have to see a sketch of that. Sounds like it coud be rickety. Like to see a sketch though.
Once again, I have done this before. I did it on JAKATAN and it worked well. It is simple. It is robust.

[palindrome]

Pal:
I think I'd have to see a sketch of that. Sounds like it coud be rickety. Like to see a sketch though.
Once again, I have done this before. I did it on JAKATAN and it worked well. It is simple. It is robust.

Something to be said for simple, I will try and draw it, but think of the bifolding airstair on 737 for example. The main attachment point is the hinge that lowers the door from its normal mount, a second hinge at roughly the mid point allows it to fold closed (think of a clamshell) and then extend open to the boarding position or open into locking pins in the transom up configuration.

Easier said than described LOL

Pal

[Bob Perry]

Pal:
Ok, I got it. Now it all has to nest in that space. But I think I could give it a try.
Nice work pal.

[Soñadora]

2 thoughts

1.) I'm with Bob. I don't think we really have a problem.

2.) If we did have a problem and we split the backstay, we could simplify it by having the split occur well above deck and the resulting 'split' stays simply going to chainplates without passing through the davit at all. If you dig around and find a rendering of Bob's 50 MotorSailer (Dobroson 50), you'll see what I mean.

I could easily model in a dink here and see how it looks.

[Soñadora]

as I have it modeled, the dingy fits just fine. We can move those ass-stays forward a bit, but you can see that we can keep the dink fairly close in. (note: this is just a generic 10' dinghy previously modeled. It is not the dinghy the client will want).

Attached Files

•  dinghy.JPG   257.2K   23 downloads

[familysailor]

Bob,

How about moving the davit crossbar a little further fwd, creating a backstay bridle which attaches to the davit arms in way of the crossbar and running some short stays from each arm to the transom. Also bury the davit arms deeply and build them out of carbon. The short stays will have a better angle, the crossbar will take up the compression load and access to the dinghy through the stern gate is improved. can you do this and not impact the mizzen boom?

 transom-2.JPG   119.76K   86 downloads

Yes!
The other configuration offended my inner "structural engineer".......... Didn't want to offend anyone, so I didn't weigh in. Probably would have required a couple of pages to say what Jose C. said.

[Tom Ray]

It is my hope that the shape of the dinghy ( I don't know what dinghy it is yet so I have been using the custom dink I did for JAKATAN on the drawings) will snug up under the davits and just miss hitting the mizzen "bobstays?" we need anorher word for these wires. The actual chainplate location is flexible and we can verify this with either 3D modelling (think Sons) or an actual mockup. Davit length may needto be adjusted but in the end I will make it work.

Bob

I've been intrigued by the dinghy issue...if the two "bob stays" where properly padded could the dinghy be drawn up with and against them. It would probably rest on about a 35-45 degree angle...securing the motor might take some thought, but I'm sure it's doable.

The dinghy would be better secured and the modifications less involved.

Just my 2 cents.

That was my thought on the subject. Let the dinghy ride at a funny angle, as long as that funny angle involves the aft side of the dinghy riding higher than the tips of the davits. Sometimes there's a big wave back there, and if you don't want a dinghy full of water, keeping the side that is facing that wave as high as possible could be good. It might look funny, but in calmer conditions you could lower the dinghy to ride level if you care how things look.

[Tom Ray]

I like the crossbar on the davits. It's a good place for the stern light.
...

If I had started with the stern door in place I would have had some options but this feature was added when the design was well along.

The crossbar would probably be a good place for the rodholders too. You could put 4 rocket launchers on there and a couple of outrigger mounts on the davit tips and troll a 4 spread.

Surprising how different people have different priorities. How could a major feature like that come along late? If you were working for me, the whole yacht would be designed as a fancy way to carry the dink around and fish while doing it. Oh, and in keeping with my policy, I would have to make you clean the whole thing inside and out and leave it completely dry before I would take possession of it. Lucky for you, there's no way I'll have enough money to hire you before you retire.

[floating dutchman]

as I have it modeled, the dingy fits just fine. We can move those ass-stays forward a bit, but you can see that we can keep the dink fairly close in. (note: this is just a generic 10' dinghy previously modeled. It is not the dinghy the client will want).

Why not move the bob stays to the END of the davids, Bring the dingy level with the deck, remove any cargo, the lift all the way up, dingy tilts and now cannot hold any water and is maybe a bit protected from a following sea?

[Gatekeeper]

[Why not move the bob stays to the END of the davids, Bring the dingy level with the deck, remove any cargo, the lift all the way up, dingy tilts and now cannot hold any water and is maybe a bit protected from a following sea?

Maybe at the same time split the backstay at the masthead and remove the cross bar all together...now that space is wide open for the fold down transom, and headroom is clear also

[Bob Perry]

If "protecting the dinghy from following seas" was an issue it would be carried in the chocks on the house top as I have described several times.
The client lives on Chesapeake Bay and huge following seas wuill not be an issue when he is at home. Offshore the dink goes on the hose.
The crossbar stays. I like it.

[Soñadora]

I've created an animation of the swim platform opening and closing. Will post it later.

It proves to me that as it is drawn, the swim platform clears everything just fine. There's also plenty of room to use the platform (it's actually more of a ladder really).

Structurally, this setup isn't as stressfull as you might think. Think of the davits as a bow sprit. There is a fore-aft compression moment, but it's relatively minimal. Personally, my intuition tells me that a steel or aluminum sub structure within the carbon fiber wouldn't be a bad idea, especially with some gussets where the crossbar meets the davits.

But, I don't know enough about CF to know if that would be overkill. Maybe just a big fillet where the crossbar meets the davits is all that's needed.

[Bob Perry]

Sons:
I'm amazed. You mean it actually works the way I drew it?

[Gatekeeper]

The crossbar stays. I like it.

You're the boss...but if people point and snicker, don't blame it on me.

[Bob Perry]

Gate:
the cross bar does several jobs. It's not an arbitrary ornament.

[Presuming Ed]

2.) If we did have a problem and we split the backstay, we could simplify it by having the split occur well above deck and the resulting 'split' stays simply going to chainplates without passing through the davit at all.

Would you have enough room with double backstays, or a really long split (90% of backstay length) led to the outer corners of the transom. It's a good looking boat, but the whole mizzen backstay to davits and triatic stay set up would give me the heeby-jeebies. If someone crashes into you, it puts the whole rig at risk. If the davits are strong enough, how much do they weigh - all that weight in the ends. And if they're made of carbon to save weight... carbon doesn't do impacts.

Ug. KISS. Were this to be my project, it would be long split backstays on both main and mizzen. No triatic.

[Hike, Bitches!]

as I have it modeled, the dingy fits just fine. We can move those ass-stays forward a bit, but you can see that we can keep the dink fairly close in. (note: this is just a generic 10' dinghy previously modeled. It is not the dinghy the client will want).

Sons, we need a 3-D PDF rendering of this area for closer inspection.

Maybe at the same time split the backstay at the masthead and remove the cross bar all together...now that space is wide open for the fold down transom, and headroom is clear also

Right, that is exactly what I was thinking...just split the backstay all the way from the top of the mizzen...those davits are shaped such that they look like if built in carbon will be the strongest part of the boat.

Oh, I live in the Chesapeake Bay too. I can't WAIT to see this baby in person some day.

[Bob Perry]

Presuming:
I posted the weight of the davits earlier.
Your idea is worth a look. But as I also said earlier I may not even need that mizzen backstay with the sweep I have on the mizzen spreaders. I just feel better with it there. I doubt very much that having the davits carried away would result in losing the entire rig. You have to pull those miz cap shrouds out of the deck first. Can't see that happening. I need to see if I have mizz boom clearance of the split backstays on the transom corners. I also need room to install chainplates on the transom corners. I'd prefer not to have them external.

I did a quick construct to see if the mizzen boom will clear split backstays with chainplates on the transom corners and it is just too close for me. I need to allow room for the boom to kick up and clear the backstay in the case of a flying jibe where the vang was off. This has to be considered. Without cutting down the mizzen boom length it's just too tight for that arrangment. For now it will stay as drawn.

[Hike, Bitches!]

Bob, what about the split backstays out to each davit? No issue with clearance there and you eliminate the 'jumper stays' under the davits...anchor the backstays to the davits themselves?

[Presuming Ed]

Presuming: I posted the weight of the davits earlier.

Sorry. Missed that.

But as I also said earlier I may not even need that mizzen backstay with the sweep I have on the mizzen spreaders.

How about just runners for when a mizzen staysail is flying?

[Bob Perry]

Presuming:
Yes, that is one of the alternative ideas I have. I like that.I would prefer that. I have 29 degrees of sweep on the mizzen spreaders now and that should do it. Before finalizing how the mizzen will be stayed I need to pick out a spar builder. At that time I will go over my options. Ideally I'd like to lose the standing backstay but for the initial round of builder bids it will stay on.

Bitches:
I don't think I can support the mizzen load on just the davits without an offsetting stay down to the transom. I'm trying to be conservative.

[Hike, Bitches!]

I am not a structural engineer...but I play one on the Internet...just add a few pounds to the dinghy to give you more support!

[treef]

This thread continues to fascinate me. Instead of drawing a kitchen for a client last night, I spent too much time on the davits and mizzen backstay for Mr. & Mrs. Lucky's 57 footer.

And in each iteration I came back to the solution as Bob drew and Sons rendered; barring a major change to the mizzen it is a logical and elegant solution. A split backstay from the mizzen masthead to each corner of the transom doesn't work, even with a longer mizzenmast crane, since the leech still snags the backstay and the boom is just a bit too long. Plus if the leech snags outside the leeward split stay which going upwind, there's almost no way to flip it back inside. A single masthead backstay with a lower split out to each davit seems unnecessarily complicated. Eliminating the backstay seems contrary to the idea of a conservative cruising yacht.

On the plus side, I grew to like the crossbar. It will be a nice thing to grab when using the stairs or when loading the dinghy. A reservation would be that it probably makes it impossible to Med-moor the boat with a stern gangway. Is that an issue?

Plus the davits themselves make excellent pee-stays. Though does an owner of a vessel like this use a pee-stay?

I have to get back to that kitchen. I don't like where the microwave ended up due to the design spiral, so I have to start over. I bet this crowd would have some opinions!

Thanks to all for the education, entertainment and the distraction!

[Soñadora]

Sons:
I'm amazed. You mean it actually works the way I drew it?

I know. Can you believe it? You would think everyone on CA was from Missouri